The invention generally relates to a high temperature resistant marking agent, especially ink, for application to a surface, especially a ceramic surface.
Such an ink is known, for example, from U.S. patent specification 5,055,137. The known ink is used for the marking of bodies. The high temperature resistant ink can be applied to cold or hot surfaces. To achieve the high temperature resistance, a mixture of a large number of different oxides which each have a certain molecular mass is used. In addition, various additives such as graphite, metals, sulfides etc. are used as stabilizers.
An object of an embodiment of the present invention is to produce a high temperature resistant marking agent from a smaller number of less expensive chemicals.
An object may be achieved for a high temperature resistant marking agent according to an embodiment of the invention by the marking agent comprising
17-20 parts by mass of iron(III) nitrate nanohydrate,
14-15 parts by mass of potassium hexacyanoferrate(H) trihydrate,
2.5-10 parts by mass of 25% strength ammonia solution and
160-200 parts by mass of distilled water.
The chemicals used are inexpensive proanalysis chemicals and distilled water. These substances can be acquired in a cost-effective manner and are available in an adequate amount. The high temperature resistant marking agent does not comprise any high temperature corrosive constituents. After subjecting the marking agent to a temperature of more than 500xc2x0 C., virtually only iron oxides are still present.
The markings produced with the new type of marking agent are readily legible both prior to being subjected to heat and also after being subjected to heat. The marking withstands are subjected to temperatures of up to 1500xc2x0 C. Prior to being subjected to heat, the marking agent has a blue color. After being subjected to heat of about 500xc2x0 C., the color changes to a brown shade. The marking agent can be produced under atmospheric conditions by the portion-wise addition and mixing of the individual chemicals with the distilled water.